A portable 3G (3rd-generation, the third generation mobile communication technology) router has characteristics of being handy, small, and exquisite, is convenient to carry, can meet a user's demand for accessing the Internet anytime anywhere, and is more and more widely applied. However, a problem of occupying too many 3G bandwidths of an operator also exists. In an application scenario where there is a fixed network access resource, such as home and office, if network traffic of a user can be switched from the 3G to a fixed network router, not only an access rate can be increased, but also traffic can be shared for a 3G network of the operator.
In the prior art, a universal serial BUS (Universal Serial BUS, hereinafter referred to as USB) to Ethernet chip is adopted to design an Ethernet base, which is used as an accessory of the portable 3G router to provide a fixed network access function for a client. In a specific application, the Ethernet base is connected to the portable 3G router through a USB interface, and is capable of switching the network traffic of the user from the 3G to the fixed network router after being connected to the fixed network router through an Ethernet line.
Currently, a USB of the portable 3G router generally adopts a USB slave (slave device) interface, so as to be compatible with a USB host (host device) interface of a PC machine. However, the USB to Ethernet chip used in an existing Ethernet base generally adopts a USB slave (slave device) interface; therefore, software is needed to transform the USB of the 3G router into a USB host, so as to match an existing USB to Ethernet chip. Moreover, a 3G portable wireless router also needs to provide a USB to Ethernet drive, so as to virtualize a drive of a transceiver packet into a drive of an Ethernet network card; and data forwarding between the USB interface and an Ethernet interface is accomplished by the 3G portable wireless router. Therefore, basic architecture of the portable 3G router needs to be modified. In addition, because the USB of the base fulfills a USB slave function, when the base performs data transmission with the portable 3G router through the USB interface, the portable 3G router cannot be charged simultaneously. Therefore, the portable 3G router and the base both need to add a charging interface, which makes a product structure complex and is adverse to saving of the cost.